Syringes are in common use today for hypodermic injection. Often these syringes are disposable syringes intended for only one use. However, these syringes are capable of repeated reuse if a user so desires. A serious problem today is that syringes are obtainable by intravenous drug addicts who repeatedly reuse and share the same syringe with other drug addicts without proper sterilization between each use. Hence, any blood-borne infectious disease that one such addict has is spread to those with whom he shares his syringes. This mechanism is thought to be a major cause of the current AIDS epidemic, as well as contributing to the spread of hepatitis, venereal disease, and other blood-borne diseases.
Recognizing this problem with the use of the injectible drugs, the present inventor has obtained U.S. Pat. No. 4,699,614, issued on Oct. 13, 1987. This patent described a non-reusable syringe having a barrel with an open end and a restricted end, a piston slidably positioned within the barrel and forming a liquid-tight seal with the interior of the barrel. A shaft is freely slidable within the barrel and extends beyond one end of the barrel. A connector engages the piston and the shaft and has a protrusion extending therefrom. A guide is formed on the shaft for receiving the protrusion of the connector. In generation, the connector is detachable from the shaft. In such invention, the connector comprises a collar holder fastened at one end of the piston, and a collar freely rotatable about the collar holder. The guide comprises a groove formed on the shaft which engages the protrusion from the connector. The guide causes the shaft to be disconnected from the piston following an injection of the liquid from the syringe.
After extensive use and experimentation with the present invention, it was found to be desirable to provide improvements to such syringe that could be manufactured and assembled less expensively, more easily, and with greater reliability. It was found that an inexpensive price of manufacture would allow the self-destructing syringes to be more widely available.
It is an object of the present invention to provide a non-reusable syringe that requires fewer parts than previous non-reusable syringes.
It is another object of the present invention to provide a non-reusable syringe that is capable of relatively simple manufacture at inexpensive prices.
It is another object of the present invention to provide a non-reusable syringe that is of inexpensive cost and is suitable for reliable widespread usage.
It is still a further object of the present invention to provide a non-reusable syringe that self-destructs following a single use, that avoids tampering, and deters the spread of fatal infectious diseases.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.